Frednes Bridge (Norwegian: Frednesbrua) is a double-leaf bascule bridge on Highway 356 in Porsgrunn Municipality in Telemark county, Norway. The 461.5-metre (1,514 ft) long bridge crosses the Porsgrunn River (Porsgrunnselva) just before it flows out into the Frierfjord at the site of Norsk Hydro's factory complex on Herøya.

Frednes Bridge Frednesbrua
View of the bridge
Coordinates	59°08′04″N 9°37′50″E / 59.1344°N 9.6306°E / 59.1344; 9.6306
Carries	Rv36
Crosses	Porsgrunn River
Locale	Porsgrunn
Characteristics
Design	Double-leaf bascule bridge
Material	Concrete and steel
Total length	461.5 metres (1,514 ft)
Longest span	60 metres (200 ft)
Clearance below	13 metres (43 ft)
Location

The bridge was completed in 1995. It is constructed of prestressed concrete with a steel drawbridge span over the main channel. It is 461 metres (1,512 ft) long, with a main span of 60 metres (200 ft), and beneath it, there is a clearance for vessels of 13 metres (43 ft) at mean water level.^[1]

Frednes was the historic name of an old district of the town of Porsgrunn as well as the name of the Frednes farm. Frednes was purchased by shipping magnate Christen Knudsen who moved there with his family in 1855. The manor house was expanded in 1865, but burned down in 1952 and was not rebuilt.^[2]